Replace tests.base part8

It is the last step to replace using openstack.common.test.
In this patch is changed for using
openstack.common.test and added needed fixtures in test classes.
Cleaning base.py and deleted TestCase class.

Change-Id: If4b5992de70fb01cf29363243fb7e50196653fff
Use wsme ClientSideError to handle unicode string

We inherit from wsme.esc.ClientSideError to handle unicode string in
error message.

Fixes bug #1200518

Change-Id: I54a185a436b0a65bef13f303d7e31911cada76d8
Merge "Replace tests.base part8"
Merge "Use wsme ClientSideError to handle unicode string"